1. Field
Apparatus and methods consistent with the exemplary embodiments relate to varifocal lens structures, methods of manufacturing the varifocal lens structures, optical lens modules including the varifocal lens structures, and methods of manufacturing the optical lens modules.
2. Description of the Related Art
Related art portable communication devices are evolving into multi-purpose electronic devices having various functions including, in addition to a calling function and a message delivery function, a camera function, a game function, a music reproduction function, and an Internet function. Also, there are efforts to integrate more functions in a small space in portable communication devices. Among various modules integrated in portable communication devices, reducing the size of a camera module requires miniaturization of an image forming optical system in the camera module. Meanwhile, an automatic focusing function, a shake correction function, and a zooming function are needed for image quality. However, in view of the adding of the functions to a camera module, the camera module is to be limited in size. An automatic focusing function may be embodied in a camera module by using, for example, a step motor, a voice coil motor (VCM), or a liquid lens. However, methods using step motors and voice coils are not appropriate for use in portable communication devices since the portable communication devices are to be limited in size. In addition, there are manufacturing costs associated with forming step motors and voice coils in batch processes.
Very small related art varifocal lens structures that have small thicknesses, that control focal distances, and that are manufactured at a wafer level are being developed. In the varifocal lens structure, a fluid chamber filled with an optical fluid is sealed with a transparent elastic membrane, and a polymer actuator is disposed on the elastic membrane. In this structure, if the polymer actuator is driven, a pressure applied to the optical fluid is changed, and due to the pressure change, the elastic membrane is deformed, thereby changing a focal distance of a lens. Varifocal lens structures may be disposed, for example, in front of a camera module and used when an automatically focusing function is carried out.
In the varifocal lens structure, an elastic membrane may be formed of, in general, a hydrophobic material. Accordingly, when an acryl-based or epoxy-based adhesive agent is used to bond the elastic membrane to a polymer actuator, an adhesive force between the adhesive agent and the elastic membrane may be decreased.